CN111939896B - Liquid catalyst for catalyzing ozone decomposition at normal temperature and its preparation method and application - Google Patents

Abstract

A liquid catalyst for catalyzing ozonolysis at normal temperature is prepared by the following method: dissolving metal salt in water, adding a complexing agent and a surfactant, and uniformly stirring to obtain a mixed solution; stirring the obtained mixed solution at room temperature to 95 ℃ for 0-40 min, then adding a solvent, crystallizing at 120-200 ℃ for 1-8 h, cooling to room temperature, performing suction filtration, filtering out solids, and dispersing the solids in the solvent to obtain the product; the active spraying liquid prepared by the invention does not need to be roasted, can be used for flexibly atomizing and spraying loads on the surfaces of objects with any shapes and materials theoretically, and can endow the objects with the capability of catalyzing and decomposing ozone after being dried, so that the space is fully utilized, the ozone is fully contacted with a catalytic material as far as possible, the environmental ozone is further decomposed efficiently, and the purpose of treating ozone pollution is achieved.

Description

Liquid catalyst for catalyzing ozone decomposition at room temperature, preparation method and application thereof

technical field

The invention relates to a liquid catalyst for catalyzing ozone decomposition at room temperature, a preparation method and application thereof.

Background technique

Air is an essential substance that human beings cannot live without for a moment, and its quality directly affects human production and life. In recent years, the problem of excessive ozone in my country has become increasingly prominent, and it has become another important regional air pollutant after PM2.5. As a strong oxidizing gas, ozone has a corrosive effect on human skin and eyes, and can strongly stimulate the mucous membrane tissue of the body. When the concentration exceeds 1×10 ^-7 (volume ratio), it will cause discomfort to the human body, resulting in asthma, bronchitis, Cardiopulmonary problems such as heart disease, further increase in concentration can even lead to death. In addition, ozone can also cause damage to the ecological environment, for example, causing necrosis and shedding of plant leaves, resulting in reduced crop production. Therefore, it is necessary to effectively control ozone pollution, which requires an efficient and safe ozone removal method.

At present, the ozone removal methods mainly include thermal decomposition method, activated carbon method, chemical liquid absorption method and catalytic decomposition method. Among them, the catalytic decomposition method is the ozone pollution control method that is generally recognized and concerned because of its safety, economy and high efficiency. The core of the catalytic decomposition method is the catalyst, and the key lies in the research and development of high-performance catalysts. Such as: CN110433795A discloses a kind of activated carbon supported MnO _x catalyst, its preparation method and its application, with divalent manganese salt, ammonium bicarbonate, activated carbon and sodium lauryl sulfate as raw materials, the catalyst precursor is prepared by co-precipitation method , and then using the method of high temperature heat treatment, an activated carbon-loaded MnO _x catalyst with MnO _x uniformly loaded on activated carbon and with controllable particle size was prepared. This catalyst was applied to catalytic decomposition of ozone materials, which can effectively catalyze the decomposition of ozone at room temperature. CN110420636A discloses a lanthanum-modified manganese oxide catalyst, its preparation method and its application. Manganese oxide is obtained by hydrothermally treating divalent manganese salt with permanganate or persulfate, and then the manganese oxide is Doped with lanthanum salt, after drying and high-temperature calcination, the lanthanum-modified manganese oxide catalyst can be obtained. The prepared lanthanum-modified manganese oxide catalyst can efficiently catalyze and decompose ozone at room temperature. Manganese oxide modified with lanthanum, which greatly shortens the time required to decompose ozone at room temperature. CN105312061 provides a catalytic material for removing ozone at room temperature, which uses porous activated carbon with a high specific surface area and a composite material based on molecular sieve as a carrier; one or more non-precious metal oxides are loaded as active components, and one or more The reductive protective agent is prepared by step-by-step impregnation process and then roasted. It can catalyze and decompose ozone by more than 95% under normal temperature and humidity conditions.

As mentioned above, researchers have reported many non-noble metal oxide ozonolysis catalysts with excellent performance. However, ambient ozone is significantly different from the exhaust gas emitted by general industrial organizations. It is not only extremely low in concentration but also highly dispersed in space. Therefore, the conventional structure catalysts reported so far cannot effectively play a role in the treatment of ambient ozone. In order to achieve efficient decomposition of ozone pollution, the following two problems must be solved: (1) How to improve the contact surface between ozone and catalyst? (2) How to improve the decomposition rate of extremely low concentration ozone on the catalyst surface? Therefore, there is an urgent need to develop a new type of ozone decomposition catalyst with better performance and full contact with highly dispersed ozone.

Contents of the invention

Aiming at the deficiencies existing in the catalytic decomposition of ambient ozone by catalysts with conventional structures at present, our solution is to design and synthesize a stable high-activity, high-specific-surface metal oxide liquid catalyst, which can be formed on the surface of a support with any structure by atomizing and spraying the loading method. Uniformly dispersed and firm high-activity catalyst film, so that it is not limited by the form of the support, and the support of any shape and structure can be turned into a catalyst, making full use of the reaction space, effectively improving the contact surface between ambient ozone and the catalyst, and improving the catalytic efficiency. A brand-new environmental ozone control scheme.

Technical scheme of the present invention is as follows:

A liquid catalyst that catalyzes the decomposition of ozone at room temperature is prepared as follows:

Dissolve the metal salt in water, add a complexing agent and a surfactant and stir evenly to obtain a mixed solution; stir the obtained mixed solution at room temperature to 95°C for 0-40 minutes, then add a solvent, and crystallize at 120-200°C for 1 ~8h, cooled to room temperature, suction filtered, and the filtered solid was dispersed in a solvent to obtain the liquid catalyst for catalyzing ozonolysis at room temperature;

Described metal salt is soluble metal salt, is selected from manganese salt, can also comprise one or the mixture of two or more arbitrary proportions in cerium salt, iron salt, copper salt, nickel salt; The form is preferably one or more of nitrate, sulfate, chloride;

The volumetric amount of water used to dissolve the metal salt is 0.1-3 mL/g based on the mass of the metal salt;

The complexing agent is selected from one of EDTA, oxalic acid, citric acid, and ascorbic acid, or a mixture of two or more in any proportion; the ratio of the molar weight of the complexing agent to the total molar weight of metal elements is 0.1 to 1:1;

Described surfactant is organic surfactant or inorganic surfactant, preferably inorganic surfactant, for example can be selected from one or more arbitrary proportions in sodium hexametaphosphate, sodium pyrophosphate, sodium tripolyphosphate Mixture; the added mass of the surfactant is 0.1% to 2% of the total mass of metal elements;

The solvent added to the mixed solution is a mixed solution of water and alcohol at a volume ratio of 0 to 1:1, and the volume dosage is 5 to 10 mL/g based on the mass of the metal salt, wherein the alcohol is absolute ethanol or ethylene glycol;

The solvent used to disperse the filtered solid is water, ethanol, propanol or a mixed solvent of two or more in any proportion, and the volumetric dosage is 20-1000mL/g based on the mass of the obtained solid;

The room temperature refers to 20-30°C.

The liquid catalyst (active spray liquid) prepared by the invention can be applied to environmental ozone treatment. Specific application methods, such as: atomize and spray the normal temperature ozonolysis liquid catalyst on the surface of any object in the environment, and form a catalytic film after drying, which can catalyze the decomposition of ozone in the environment.

Compared with prior art, the beneficial effect of the present invention is:

1. The present invention has simple process, low cost and wide application range.

2. The present invention forms an active structure at a relatively low temperature of 120-200°C, which can effectively prevent high specific surface area and abundant oxygen vacancies from being destroyed by roasting, thereby obtaining a high-performance ozone decomposition catalyst at room temperature.

3. The existing preparation methods of ozone decomposition catalysts at room temperature generally form the final shaped catalysts by roasting. These catalysts with conventional structures cannot fully contact with highly dispersed ambient ozone, which largely limits the catalytic effect of ozone decomposition; and this The invention prepares the active spray liquid without roasting. In theory, it can be flexibly atomized and sprayed on the surface of objects of any shape and material. After drying, these objects can be endowed with the ability to catalyze and decompose ozone, making full use of space. Make the ozone fully contact with the catalytic material, and then decompose the ambient ozone efficiently, so as to achieve the purpose of controlling ozone pollution.

Description of drawings

Fig. 1 is the physical map of the manganese oxide room temperature ozonolysis liquid catalyst prepared in Example 1 and the nitrogen adsorption-desorption curve and S _BET of the active nanoparticles therein.

Fig. 2 is the activity test figure of embodiment 6.

Fig. 3 is a diagram of the testing device of Examples 7-12.

Fig. 4 is the catalytic decomposition of ozone functionalization of filter cotton at room temperature in Example 7.

Fig. 5 is the activity test figure of embodiment 7.

Fig. 6 is the catalytic decomposition of ozone functionalization of the sunscreen net at room temperature in Example 8.

Fig. 7 is the activity test figure of embodiment 8.

Fig. 8 is the catalytic decomposition of ozone functionalization of the fabric of Example 9 at room temperature.

Fig. 9 is the activity test figure of embodiment 9.

Fig. 10 is the catalytic decomposition of ozone functionalization of bricks at room temperature in Example 10.

Fig. 11 is the activity test figure of embodiment 10.

Fig. 12 is the function of catalytic decomposition of ozone at room temperature of stones in Example 11.

Fig. 13 is the activity test diagram of embodiment 11.

Fig. 14 is the catalytic decomposition of ozone functionalization of leaves in Example 12 at room temperature.

Fig. 15 is the activity test figure of embodiment 12.

Detailed ways

The present invention will be further described below through specific examples, but the protection scope of the present invention is not limited thereto.

Example 1

Make a solution of 7.55g manganese sulfate, 1.46g EDTA, 2.75×10 ^-3 g sodium pyrophosphate and 22.7mL water, put it in a 70°C water bath and stir for 20min, after cooling, add 37.8mL water and absolute ethanol mixture (volume ratio 1:1) and transferred to a crystallization kettle, placed in an oven at 180°C for crystallization for 3 hours, cooled to room temperature, and suction filtered. The obtained solid was dispersed by adding 55mL of ethanol to obtain a concentration of 5×10 ^-2 g/mL Manganese oxide room temperature ozonolysis liquid catalyst.

Example 2

Mix 6.30g of manganese chloride, 10.10g of ferric nitrate, 6.75g of oxalic acid, 8.29×10 ^-2 g of sodium tripolyphosphate and 49.2mL of water to form a solution, place it in a water bath at 90°C and stir for 30min, after cooling, add 164mL of water and ethylene glycol Alcohol mixed solution (volume ratio 1:1) was transferred to a crystallization kettle, placed in a 120°C oven for crystallization for 8 hours, cooled to room temperature and filtered with suction, and the obtained solid was dispersed by adding 4140mL of water to obtain a concentration of 1× 10 ^-3 g/mL ferromanganese binary composite oxide liquid catalyst for ozonolysis at room temperature.

Example 3

14.32g of manganese nitrate, 8.08g of ferric nitrate, 1.09g of cerium nitrate, 12.0g of citric acid, 7.32×10 ^-2 g of sodium hexametaphosphate and 2.3mL of water were made into a solution, and 164.4mL of absolute ethanol was added and transferred to crystallization kettle, placed in an oven at 140°C for crystallization for 4 hours, cooled to room temperature, and suction filtered. The obtained solid was dispersed by adding 180 mL of propanol to obtain a ternary composite oxidation of manganese, iron and cerium with a concentration of 2×10 ^-2 g/mL. A liquid catalyst for room temperature ozonolysis.

Example 4

Make a solution of 4.53g manganese sulfate, 1.62g ferric chloride, 0.40g cerium sulfate, 1.34g copper chloride, 4.90g citric acid, 2.98×10 ^-3 g sodium tripolyphosphate and 20.0mL water, and place at 60°C Stir in a water bath for 40 min, add 63.2 mL of absolute ethanol after cooling and transfer to a crystallization kettle, place in a 160°C oven for crystallization for 6 h, cool to room temperature and perform suction filtration, add 300 mL of a mixed solution of water and ethanol to the obtained solid (volume ratio of 1:1) to obtain a liquid catalyst for ozone decomposition at room temperature of manganese-iron-cerium-copper quaternary composite oxide with a concentration of 1×10 ^-2 g/mL.

Example 5

5.03g of manganese chloride, 8.00g of ferric sulfate, 0.88g of cerium chloride, 1.60g of copper sulfate, 3.65g of nickel nitrate, 21.63g of EDTA, 5.47×10 ^-2 g of sodium pyrophosphate and 48.0mL of water were prepared into a solution, placed in Stir at room temperature for 40 minutes, add 115.0 mL of water and ethanol mixture (volume ratio 0.5:1) and transfer to a crystallization kettle, place in a 200°C oven for crystallization for 1 hour, and suction filter after cooling to room temperature to obtain a solid Add 1000mL of mixed solution of water, ethanol and propanol (volume ratio 14:5:1) to disperse, and then obtain a five-component manganese-iron-cerium-copper-nickel composite oxide with a concentration of 5.5×10 ^-3 g/mL at room temperature and ozonolysis liquid catalyst.

Example 6

The manganese oxide room temperature ozonolysis liquid catalyst prepared in Example 1 was sprayed on the cordierite honeycomb ceramic substrate, and after drying, a Mn/cordierite monolithic catalyst with a loading capacity of 2% was obtained.

The catalytic ozone decomposition performance test was carried out in a fixed bed reactor. The prepared Mn/cordierite monolithic catalyst (M/CH) was put into a U-shaped reaction tube and placed in a 25°C water bath. A certain humidity (0-20h: RH=60%, 20-30h: RH=40%, 30-40h: RH=90%, 40-45h: RH=0%) is continuously introduced into the reaction tube, and the concentration is 45mg ·m ^-3 ozone simulation gas (balance gas is air), the space velocity is 3000h ^-1 . The tail gas is detected by infrared, converted into corresponding concentration according to the standard curve, and the ozone decomposition rate is calculated, and a commercial ozone decomposition catalyst (COC; XRF analysis, the main composition is: w (C) 95.06%, w (Mn) 1.39%, w (Fe) 0.820%, w (Si) 0.782%, w (Na) 0.394%, w (Al) 0.368%, w (Mg) 0.214%, w (S) 0.134%) as a comparison, the results are shown in Figure 2.

Example 7

The ferromanganese binary composite normal temperature ozonolysis liquid catalyst prepared in Example 2 is sprayed on the filter cotton (as shown in Figure 4), and after drying, the filter cotton with the ability to catalytically decompose ozone at normal temperature is obtained; it is placed as shown in Figure 3 The device shown is used for catalytic decomposition of ozone test, and the results are shown in Figure 5.

Example 8

Spray the manganese-iron-cerium ternary composite normal temperature ozonolysis liquid catalyst prepared in Example 3 on the sunscreen net (as shown in Figure 6), and obtain the sunscreen net with the ability to catalytically decompose ozone at normal temperature after drying; The device shown was used for the catalytic decomposition of ozone test, and the results are shown in Figure 7.

Example 9

Spray the manganese-iron-cerium-copper quaternary compound room temperature ozonolysis liquid catalyst prepared in Example 4 on the cloth (as shown in Figure 8), and obtain the cloth with room temperature catalytic decomposition of ozone after drying; place it in the place shown in Figure 3 The device shown is used for catalytic decomposition of ozone test, and the results are shown in Figure 9.

Example 10

Spray the manganese-iron-cerium-copper-nickel five-component composite room temperature ozonolysis liquid catalyst prepared in Example 5 on the brick (as shown in Figure 10), and obtain the brick with room temperature catalytic decomposition of ozone after drying; place it in Figure 3 The shown device was tested for catalytic decomposition of ozone, and the results are shown in FIG. 11 .

Example 11

The manganese oxide room temperature ozonolysis liquid catalyst prepared in Example 1 is sprayed on the stone (as shown in Figure 12), and after drying, the stone with the ability to catalytically decompose ozone at room temperature is obtained; it is placed in the device shown in Figure 3 Carry out catalytic decomposition ozone test, the result is shown in Figure 13.

Example 12

The ferromanganese binary composite room temperature ozonolysis liquid catalyst prepared by embodiment 2 is sprayed on the leaves (as shown in Figure 14), and after drying, the leaves with the ability to catalytically decompose ozone at room temperature are obtained; The device was tested for catalytic decomposition of ozone, and the results are shown in Figure 15.

Example 13

The prepared room temperature ozone decomposition liquid catalyst can be atomized and sprayed on the surface of any object (road, utility pole, wall, cloth, paper, etc.) in the environment, and after drying, a catalytic film can be formed, which can be used to catalyze and decompose ambient ozone.

Claims (9)

1. a liquid catalyst for catalytic ozonolysis at normal temperature, is characterized in that, is prepared as follows: Dissolve the metal salt in water, add a complexing agent and a surfactant and stir evenly to obtain a mixed solution; stir the obtained mixed solution at room temperature to 95°C for 0-40 minutes, then add a solvent, and crystallize at 120-200°C for 1 ~8h, cooled to room temperature, suction filtered, and the filtered solid was dispersed in a solvent to obtain the liquid catalyst for catalyzing ozonolysis at room temperature; The metal salt is a soluble metal manganese salt; The complexing agent is selected from one of EDTA, oxalic acid, citric acid, ascorbic acid or a mixture of two or more in any proportion; The surfactant is selected from one of sodium hexametaphosphate, sodium pyrophosphate, sodium tripolyphosphate or a mixture of two or more in any proportion; The solvent added to the mixed solution is a mixed solution of water and alcohol at a volume ratio of 0-1:1, wherein the alcohol is absolute ethanol or ethylene glycol. 2. the liquid catalyst of normal temperature catalytic ozonolysis as claimed in claim 1, it is characterized in that, described metal salt is the mixture of soluble metal manganese salt and other soluble metal salts, and other soluble metal salts are selected from cerium salt, iron salt, copper Salt, nickel salt, or a mixture of two or more in any proportion. 3. The liquid catalyst for catalyzing ozone decomposition at room temperature as claimed in claim 1 or 2, wherein the volumetric amount of water used to dissolve the metal salt is 0.1 to 3 mL/g based on the mass of the metal salt. 4. The liquid catalyst for catalytic ozonolysis at room temperature according to claim 1 or 2, characterized in that the ratio of the molar weight of the complexing agent to the total molar weight of metal elements is 0.1-1:1. 5. The liquid catalyst for catalyzing ozone decomposition at room temperature as claimed in claim 1 or 2, characterized in that the added mass of the surfactant is 0.1% to 2% of the total mass of metal elements. 6. The liquid catalyst for catalyzing ozonolysis at room temperature as claimed in claim 1 or 2, wherein the volumetric amount of the solvent added in the mixed solution is 5-10 mL/g based on the mass of the metal salt. 7. as claimed in claim 1 or 2, the liquid catalyst of catalytic ozonolysis at normal temperature, is characterized in that, the solvent that is used to disperse and leach solid is water, ethanol, propanol one or two or more mixed solvents of any ratio, The volumetric dosage is 20-1000mL/g based on the mass of the obtained solid. 8. the application of the liquid catalyst of catalytic ozonolysis at normal temperature as claimed in claim 1 or 2 in environmental ozone treatment. 9. The application as claimed in claim 8, characterized in that, the method of application is: atomize and spray the liquid catalyst that catalyzes ozonolysis at room temperature on the surface of any object in the environment, and form a catalytic film after drying, which can Ozone in the environment undergoes catalytic decomposition.

Images